Method of cold heading



May 21, 1935.

A. T. slvlTER 2,001,981

HOD 0F L EAD NG v Filed Ja'n. 22, 1951 JNVENTOR.

1:34 Fg@ a.y BY- M P Patented May 2l',' 1935 PATENT OFFICE METHOD F,V COLD HEADING ArthurT. Siviter, Detroit, Mich., assigner to- Budd Wheel Company, Philadelphia, Pa., a' corporation of Pennsylvania Application January 22, 1931, Serial No. 510,411

Claims.

My invention has for its object improvements in the art ofrcoldheading and relates more particularly to an adequate control of a blank which is to be cold headed in several successive operations. A more particular object has been to Weliminatev the difficulty heretofore encountered in successive cold heading processes using a common female die and a hollow punch member incident to the tendency of the blank which was in process of cold heading to recede with the punchand become jambed therein between successive headlng operations performed by successive punches. I'have obviated this diiliculty by forming one or `more of my female dies of a configuration adaptf' ed to insure the jambing of the nut within the female die assembly during the recession of the punch.

Other objects and advantages of my invention will be obvious from a reading of the subjoined specification in the light'of the attached drawing, in which: v

Fig. 1 is a central sectional view of my die `assembly illustrating the rst step in my improved process.

Fig. 2 is a. similar View through the female die and the rst punch coacting therewith illustrating the second step in the process.

Fig. 3 illustrates a further step. Figs. 4 and 5 illustrate my two female dies, and Fig. 6 illustrates the stud constituting the nished product of my method.

Referring to the drawing by reference characters, 'the numeral I 0 indicates `a. blank which .is to be cold headed, the cold heading operation in the present case constituting the formation of a trunk stud having an enlarged annular flange 24 in its central region and a second enlarged portion 23 adjacent thereto. The cold heading operation by which the stud is formed from the blank I0 is performed in two successive steps in the rst of which the enlarged portion 23 is formed by upsetting the blank within the female dies. The second step consists in the formation of the annular collar 24 by thev coaction of one of these female dies with a seconddie in the nature of a. punch.

These operations were performed in accordance with the prior art by the coaction of a single set of female dies with a pair of punches which were mounted for reciprocatory motion in two 'dimensions at right angles to each other in order were provided with hollow portions adjacent their outer ends adapted to receive the end of the blank I0 and considerable difiiculty was encountered incident to the tendency of the blank to be slightly upset within the hollow end of the punch and to jamb within the punch and to be withdrawn therewith.

My improved cold heading die assembly is similar to those of the prior art except for certain important details as to the formation of one or more of the dies whereby thisjambing 4effect is obviated. This die assembly consists of the die holder II in which are mounted front and rear female dies I2 and I3 held in place between Oa suitable anvil I 4 on the rear side and a shoulder I 6 formed adjacent the outer end of the die holder to coact with a complemental shoulder I 6 lon the outer die I2. An ejector I 57 is adapted to reciprocate within an opening in the anvil I4 and eject the finished blank at the end of the cold heading operation.- This ejector performs the additional function of acting as a limiting stop for the movement of the blank into the femalev die assembly. The punch assembly consists of a head I8 withinwhich a pair of punches I9 and 20 are mounted, the head I 8 being provided with means (not shown) for effecting a reciprocation thereof toward and from the solid female die assembly and at right angles thereto, these motions effecting the heading operations and the alignment of successive punches with the female die assembly, respectively. By solid female die, is meant a. die which is not divided longitudinally of the die recess for lateral separation at the time of extrusion, although it may be formed of laterally-divided `parts to be held together while the blank Ais extruded longitudinally therefrom, or composed ofa plurality of die sections, as shown in the drawing, or the equivalents thereof.

Each of .the punches I 9 and -20 is provided with a hollow bore adapted to receive the end of the stud in process of formation. lThe reciprocation of the punch I9 upsets a portion of the blank within the dies I2 and I3 and thus forms the enlargement 23 upon the body of the stud. In the second cold heading step, in which the punch 20 coacts with the female dies, the collar 24 is formed by the upsetting of the metal adjacent the center of the stud within -reoessed portions 2| and 22 formed within the meeting ends of the punch 20and die I2 respectively. Upon the completion of the cold heading operation suitable threads are formed upon the stud to form the finished article of Fig.- 6.

In order to prevent the retreat of the stud with the punch I9, the'stud is provided with p from the mouths of the dies.

this formation a part of the metal of thestud.

. thefemale die assembly of the female dies, this portion tapering away from the outer end of the dies. In order to effect this formation one or both of the dies is provided with a bore 25 tapering slightly away As a result of an enlarged portion adaptedvto jamb Within one' is upset within the bore and jambed within the female die or dies and prevented from being withdrawn with the punch I9. As a consequence of this fact the blank is retained firmly within until after the second die 20 has formed the annular collar 24 thereon and retreated from the female dies. After this operation the ejector I5 is actuated to force the finished blank out of the female die assembly. In forcing the stud from this assembly the conical configuration thereof is destroyed incident to its passage through the most restricted portion of the dies. My invention thus consists in the formation of a temporary truncated cone upon the body of the stud to insure its retention within the female die during the entire cold heading operation. Even though the end of the blank which is received within the punch I9 be upset sufficiently to cause a tendency to jamb within the punch, the jambing within the dies I2 and I3 incident to the formation of the truncated cone will exert a grip upon the blank overcoming this tendency to recedewith the punch.

While I have illustrated but a single embodiment of my invention, thatothers will be obvious to those skilled in the art and I do not accordingly intend to be limited except by the scope of my subjoined claims as interpreted in the light of the prior art and the generic spirit of my invention.

I claim:

1. The method of cold heading a metal blank,

in successive steps which comprises upsetting plural portions of said blank within a female die in such a manner that said upset portions flare away from the mouth of the respective parts of said die and become jambed therein, and performing successive cold heading operations by the coaction of successive punches with said female die and extrudingsaid upset blank outwardly of said die through the mouth thereof.

2. The method of cold heading a metal blank in successive steps through the coaction of a plurality of dies on the one hand with a single die on the other which comprises effecting .a jambing of the blank within plural portions of the single die flaring outwardly away from the v point of entry thereof and performing theI successive cold hea'ding operations by the coaction of the first-named dies successively with said single die and forcing said formed blank outwardly through the point of entry of said die, the said single die with the flaring portions being a solid die. y

3. A die assemblyv adapted for successive coaction with a plurality of opposed dies, said assembly including a solid female die having plural portions of its bore flaring away from the point I wish it to be understood of entry and ejection of the blank with respect thereto.

4. The method of cold heading a metal blank in successive steps through the coaction of a plurality of dies on the one hand with a single die l 5 on the other which comprises forming aplurality l of flared portions on said blank within the single f v die and performing the successive cold heading operations by thecoaction of the first-named dies successively with said single dies and ejecting said formed blank out of said die through the point of entry of said blank into said die to reform the portions of the blank formed by said flared die portions.

5. The method of cold heading a metal blank in successive steps which comprises upsetting and jambing portions of the blank within successive parts of a solid female die and performing successive cold heading operations by the coaction of successive punches with said female die and ejecting said formed blank out of said die through the point of entry of said blank into said die.

, 6. The method of cold heading a metal blank in successive steps which comprises upsetting and jambing portions of the blank within successive parts of a female die in such a manner that the upset portions flare away from the mouth o f the die and performing successive cold heading operations by the coaction of successive punches with said female die and ejecting said formed blank out of said die through the point of entry of said blank into said die to destroy the flares of said portions..

7. A die assembly for successive coaction with a plurality of opposed dies, said assembly including a female die consisting of separate die blocks each having a portion of its bore fiaring away from'the point of entry and ejection of the blank with respect thereto.

8. The method of cold heading a metal blank through the coaction of a plurality of dies on one hand with a single die on the other which comprises jambing different portions of the blank in successive parts of said single die, and thereafter extruding said blank through the mouth of said single die to accurately size the blank. l 9. The method of cold heading a metal blank through the coaction of a plurality of dies on one hand with a single die on the other which comprises jambing different portions of the blank in successive parts of said single die, and therefter extruding said blank through restricted portions of said single die'to accurately size the blank.

10. The method of cold heading a stud which comprises forcing a metal blank into a femaleA die. having plural contours while upsetting said blank in the same. whereby to form tapering enlarged portions thereupon flaring away from the pointof entry of said blank in said die sections, and whereby said blank is jammed in said die sections, further upsetting said blank to form a shoulder substantially centrally thereupon, and withdrawing the cooperating die element and ejectingA said blank through the reduced size openings of said contoured female die.

ARTHUR T. SIVITER. 

